It is known that a fuel injection device (hereinafter referred to as an injector) and spark plugs are arranged in an intake passage and combustion chambers of an internal combustion engine.
Further, a variable valve timing device has been put into practical use which varies the valve timing of engine valves such as intake valves or exhaust valves by enabling the rotational phase of a camshaft to be varied relative to a crankshaft. The variable valve timing device includes a variable valve timing mechanism having a first rotational body, which is drive-coupled to the crankshaft, and a second rotational body, which is drive-coupled to the camshaft. In this structure, the first rotational body and second rotational body are rotated relative to each other by hydraulic pressure or the like. This varies the rotational phase of the camshaft relative to the crankshaft changes thereby varying the valve timing.
Another known variable valve timing device includes an “intermediate lock mechanism” that fixes the valve timing to a range between the most retarded phase and the most advanced phase, which is the variable range of the relative rotational phase, at a phase excluding the two ends of the range (hereinafter referred to as intermediate lock phase).
Patent Document 1 discloses a control that sets the relative rotational phase of the variable valve timing mechanism to the intermediate lock phase when starting the engine. If the relative rotational phase is not at the intermediate lock phase when starting the engine, the variable valve timing mechanism is controlled so that the phase is set to the intermediate lock phase.
In this state, even when fuel injection is performed before the phase is varied to the intermediate lock phase, the fuel may not be ignited. Collection of fuel on the spark plug may lower the ignition capability of the spark plug and adversely affect startability of the engine.
Accordingly, in patent document 1, the fuel injection is controlled so that it does not start until the relative rotational phase of the variable valve timing mechanism is determined as having reached the intermediate lock phase. The determination is made by monitoring whether or not the valve timing is fixed at the intermediate lock phase.